Characteristics : Total length of the body is about 61cm. Its size is almost same as wild dock and domestic dock. It has dark brown color. Although female and male is alike, male’s 위·아래꼬리덮깃 are more like dark brown color than female’s. Male’s cheeks seem to be brighter than female’s. Except light brown cheeks, its whole body is uniformly dark brown. A vivid third-wing feather is seen well from a distance. The tip of its black beak has yellow color, also its leg orange color.

Ecology : It commonly breeds at the water edge, which came to the south pass the winter as a group. It makes a round nest in the bushes of grassland or hill on a pond and reservoir.

Where you can see this species at Dongbaekdongsan : It comes to Jeju as a winter migratory birds, but some of them breed as resident bird. In Camellia hill, we can see it daytime by a pond, feather and the traces eaten by rapacious birds are observed.